Can the energy in a wave (energy type) destroy solid objects?

According to EE husband:

Energy hitting a rock wall will lead to some being absorbed, some being reflected. As it absorbs energy, it gets hotter.

If they absorb the energy, does that mean if you have a wave with enough energy to it, that as the energy is absorbed by the solid that it could absorb too much too remain as a solid and shake itself apart from the violent movement of its own atoms/molecules that would arise from holding that energy?

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Yes. That is just a phase change. The same thing happens when you put a piece of ice into a glass of warm water. Think also of laser cutting tools, or high-frequency ultrasound used to heat tissue.

And the walls of Jericho came crashing down as Gabriel blew his horn...or something like that.

Also, it might be helpful if you defined what sort of wave? A wave is a disturbance of some sort that passes through a medium. Are you talking about a single pulse or a continuous onslaught? What is generating the wave?

An ocean wave is no different from any other wave. It is kinetic energy moving through the water. When you say an energy wave, do you mean light?

Here's a simple definition of a wave:
http://paws.kettering.edu/~drussell/Demos/waves-intro/waves-intro.html

LOG said:

So, I may be over-simplifying it, but here goes.
The question arose because I'm wondering at the feasibility/effects of a weapon that generates vibrations in order to destroy.

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Absolutely. That's how we use ultrasound to destroy kidney stones.

The tricky thing is impedance mismatches. That is why we use gel between the ultrasound generator and the person - because if we don't do this almost all the energy simply echoes back when it hits the tiny air gap. And the part that does make it through the airgap will mainly echo back when it hits the body!

That is why if you shout at a wall you hear an echo - but if you shout at a swimming pool it doesn't echo as much.

What this means is that most of the energy putting out by the weapon will be reflected when it strikes the object it is aimed it.

There's good news though - some substances like crystals are extremely sensitive to certain frequencies because they resonate at those frequencies.

You might use that in your fictional weapon - you don't have to destroy the entire of the target - just a sensitive part.

Anyway - good luck with it,

Mac

There used to be a bridge out west that shows the answer is an absolute "Yes". If a bridge can be destroyed by undirected wind energy setting up a standing wave think about what could happen with directed vibratory energy using just a little feedback to detect the standing wave point in any structure and virtually instantly tuning the wavelength of an energy field or wave to that frequency.

I tried to find this vid on Discovery's website, but I couldn't locate it:

http://www.youtube.com/watch?v=kJFp2YSk_Fw

The Mythbusters tested Nikola Tesla's 'earthquake machine'. http://en.wikipedia.org/wiki/Earthquake_machine

The third part of the video has them testing it on an actual bridge. Not to spoil anything, but it didn't work. Yet, they could feel the vibrations set up by a tiny little weight for a fair distance along the bridge's length.

You'll need to be more specific about the kind of wave and the nature of the medium (if any) through which it travels. Sound waves and the initial P-waves of earthquakes, for example, are compression waves which travel by compressing and releasing tension within a medium along the direction of wave travel. Shear waves travel with a motion perpendicular to the direction of travel. Water waves travel by moving the liquid medium in an essentially circular motion.

And if your weapon is to be used in space, it essentially has no medium to travel through. The only pure energy waves that can travel through a vacuum are electromagnetic (X-rays, gamma-rays, infrared, light, radio waves). If powerful enough, these most certainly could destroy a physical object through generation of heat upon impact.

Short answer: yes. Any solid matter has a specific set of physical characteristics, such as and relevant to this, tensile, compressive, torsional and other strengths. Overcome those and the material fails.

Long answer: it depends on the material. Saturated clay would take a tremendously powerful vibration to splatter. Something on the order of one big impulse of force. A crystal goblet can be shattered by an opera singer by holding just the right note for a while. The impulse that splatters the clay would pulverize the goblet into glass sand.

Gravity, acoustics, electromagnetism, etc. there are plenty of ways to do it. Just none feasible with Earth's present level of advancement. But, if you posit that a certain level of advancement has been reached in a fictional setting, go for it. Just keep in mind that you're talking about a lot of energy needing to be imparted fairly quickly, before it can dissipate, but not more than is necessary to destroy the object at hand.

LOG said:

So, I may be over-simplifying it, but here goes.
The question arose because I'm wondering at the feasibility/effects of a weapon that generates vibrations in order to destroy.

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Explosions generate lots of waves. In particular shock waves are notoriously destructive. In the case of the aftermath of the planes hitting the Twin Towers, another building collapsed as a result of the vibrations from the collapse of the World Trade Center. So, yes, massive vibrations will destroy things, but sometimes the sources are overly obvious. As another example, to sink a battleship that had antitorpedo bulges, in theory the best method was to explode a torpedo under the keel (using the magnetic field of the ship to trigger the torpedo) and use the shock wave propagating through the water to snap the ship in half. In reality of course, explosions and waves and triggers act in unexpected ways and waves going through ships from torpedos in the bow can "break the back" of a ship just as thoroughly.

http://en.wikipedia.org/wiki/Shock_wave

LOG said:

How does a wave moving differently change matters as far as being able to destroy?

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A good example would be the various forms of waves generated by an earthquake. The initial pulse, the P-wave, is compressional, like a sound wave. It travels faster that the other disturbances, but seldom causes much physical damage, as it doesn't displace material greatly. The next wave to arrive, the S-wave, has an up-down shearing motion, and can be highly destructive in big quakes. The last waves to arrive are named Love and Rayleigh waves, affect only the surface layers of the earth, and these are the most destructive of all. The Love wave has a lateral shearing motion, and the Rayleigh wave rolls, like an ocean wave.

Also, compressional waves, such as sound, will travel through fluids and solids, but shear waves will not travel through fluids. Functionally, depending on its nature, an energy wave can destroy a solid in either of two ways: vibrational energy (think of a wine glass being shattered by a particular frequency of sound) or heating (e.g., a laser).

Also it's because a lot of materials aren't isotropic in nature (e.g. they aren't as strong in all directions). An example is concrete. Concrete is as strong as steel is, in compression, but is weak when in tension (pulled apart), shear, or torsion (twisted). Depending on the nature of the wave, the material can tolerate it more easily.

Pthom said:

Yes.

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The 'yes' might be more convincing if the machine actually worked!

Mac H. said:

The 'yes' might be more convincing if the machine actually worked!

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It did work, sort of, as tested by the Mythbusters:
http://en.wikipedia.org/wiki/MythBusters_(2006_season)#Episode_60_.E2.80.93_.22Earthquake_Machine.22

It's notable that the oscillator did produce vibrations in the bridge that could be felt all along the length, but it did not cause anything like the shaking destruction Tesla described in his lab.

Thing is, we're talking about an oscillator moving a few ounces of metal. What if it moved a few pounds? I'd like to see that.

It did work, sort of ...

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Sort of? The problem is that a lot of nonsense about the capabilities of this machine is continually repeated.

Just google it - look at how many people claim that it caused an earthquake in 1898.

Now search newspapers from New York in 1898.
Notice anything?

Sure - there are plenty of references to Tesla giving public talks about how useful his 'mechanical oscillator' might be in the future ... but where are the frenzied reports of an earthquake?

It probably did cause shaking destruction in his lab. Anyone who has ever mounted something off centre on a lathe can appreciate how much it can shake the furniture around. And that's only an eccentric mass of a few kilos.

Mac
(PS: Unfortunately google is now refusing to provide access to their scanned library of out-of-copyright newspapers and magazines so it is difficult to research properly. A few years ago google provided total access to out-of-copyright material. But no more.

The good old days)

More to the point, and apropos to the OP, small harmonic vibrations can and do cause significant damage. Did Tesla's devise cause an earthquake? No. Could it, or some similar device, bring down a bridge? Of that I have no doubt. Go stand on a major urban bridge and see how it feels when the light rail goes by. Engineers take great care to design structures so unavoidable vibrations are random and wave effects do not take out their creations.

That doesn't mean such structures are invulnerable. Vibrations are the result of various wave propagations and as has been more than well documented, our structures are not immune to the stresses caused by them.

The problem in creating a weapon that uses such effects is that it is very difficult to know at just what frequency a structure is most vulnerable.

It's not that hard to find out what the natural frequency of a structure is. All I need a few accelerometers (I've done it before). The thing is you still need a lot of energy to do anything destructive. Most buildings and bridges are designed to move, and even if you hit the natural frequency and get the structure moving, it's not likely to hurt anything unless you've got enough energy to impart more motion.

However, I can give you a good example of where I have heard of structures being damaged by vibration. It comes from trains breaking the sound barrier in the ground (what, sound barrier you say!). What happens is that the trains moving across the ground transmit energy into the ground as they move (e.g. the tracks deforming under their weight, along with vibrations from the rolling of the train, etc.). Now where it gets interesting is that in certain types of soil conditions, the train effectively goes "super sonic" with respect to the ground (really it has more to do with the compressability of the soil). This creates a big compression wave, that propagates through the ground, and basically acts like a localized earthquake. Basically the issue happens when you have soft fill/clay that is located near railroad tracks.

Everyone ok?

Dommo said:

It's not that hard to find out what the natural frequency of a structure is. All I need a few accelerometers (I've done it before). The thing is you still need a lot of energy to do anything destructive. Most buildings and bridges are designed to move, and even if you hit the natural frequency and get the structure moving, it's not likely to hurt anything unless you've got enough energy to impart more motion.

However, I can give you a good example of where I have heard of structures being damaged by vibration. It comes from trains breaking the sound barrier in the ground (what, sound barrier you say!). What happens is that the trains moving across the ground transmit energy into the ground as they move (e.g. the tracks deforming under their weight, along with vibrations from the rolling of the train, etc.). Now where it gets interesting is that in certain types of soil conditions, the train effectively goes "super sonic" with respect to the ground (really it has more to do with the compressability of the soil). This creates a big compression wave, that propagates through the ground, and basically acts like a localized earthquake. Basically the issue happens when you have soft fill/clay that is located near railroad tracks.

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Ohhh, This is interesting. Probably what is happening to our local town pool. It is about 50 yards from the train tracks and keeps getting cracks. Smaller ones get patched, but a larger one has opened and they continuously have to fill the pool.
Unfortunately no money to move the pool elsewhere, so looks like we are stuck with patches and a high water bill every summer. lol

I've read through the posts and I generally agree. I'd just like to add a few things. First of all, in solids there are two types of waves, longitudinal and transverse. One has the motion of the substrate parallel and perpendicular to the motion of the wave propagation (respectively). So the OP stated that ocean waves might be different from sound waves in this respect. But I don't think that waves of physical materials will necessarily have a different type of behavior in this respect. There are probably detailed dynamics that will capture a difference in behavior, but I imagine they act very much in the same way when hitting a different material.

In fact, I think you can think of ocean waves as a good example. When they hit a different material, there is an impedance mismatch (i.e. a material with different density etc), and hence a deposit of energy. There is also a certain amount of absorption and reflection, all depending on the materials, speeds and frequencies involved.

Though some speeds of sounds can be calculated accurately, in terms of a practical weapon, i'd be surprised if someone EVER designed one to be tailored to travel through a certain material and deposit its material into another material. Just seems far fetched.

On the resonance issue. If a particular resonance frequency is your concern, there are a few rules of thumb to consider. The stiffer a material is, or the higher the mass of the resonator, the higher the frequency. Think of banging on a handrail. if it's thin and weak, it vibrates back and forth slowly, but if its heavy and stiff it 'rings.'

anyway, I thought i'd just add a few things to this discussion, though I have agreed with most of the discussion above...